Update readme.md

Author: IG-JM

DataPresenter.DataSources.OData/readme.md

@@ -72,3 +72,4 @@ _**NOTE:** The XDP can use the APDSP in all its views (GridView, CardView etc.)
   * New properties added to the XDP:
     + **DataPresenterBrushKeys.DataPendingOverlayBrushKey** – Defines a _ResourceKey_ used to identify a brush resource that is referenced by XDP templates as a _DynamicResource_ and  used to color the cell area background when the data for the cell is pending – i.e., it has been requested but has not yet been delivered. 
     + **DataRecordCellArea.IsDynamicDataPending** - Returns true when the data for a **DataRecord** has been requested but has not yet been delivered.
+    + **DataPresenterBase.IsAsyncDataPending** - Returns true if any of the currently visible records are awaiting data as the result of an asynchronous data fetch, otherwise returns false.  _**NOTE:** This property only reflects the data fetching status of **currently visible records**.  The property will return false even when there are records which are currently 'out of view' and awaiting data as long as all 'currently in view' records are not awaiting data._  This property can be helpful if you want to display a busy indicator while data is being fetched for the records currently in view.  Please refer to the [**Sample Application**](https://github.com/Infragistics/DataSource-Reference-Implementations/tree/master/DataPresenter.DataSources.OData/DataPresenter.DataSources.OData.SampleApp) for an example of how to accomplish this.